Algorithms are being developed and tested for aiding in numerical taxonomy of feature by strain matrices to large to be analyzed by existing programs. Both segmentation and heuristic approaches are being investigated. A program has been developed and is being tested to compare and evaluate methods and/or laboratories when characterizing the same set of strains. The usual statistical packages are not useful because of the predominantly binary (i.e., discontinuous) nature of the data. The algorithm allows comparison of tests of laboratories at the levels of the individual strain (with replicable determinations), species, genus, and overall set for determination of test method equivalences and/or inter-laboratory consistency. Computer graphic algorithms are being tested to aid microbiologist in visualizing individual similarities as well as hierarchical group memberships among strains.